1. Field of the Invention
The present invention relates to a plasma display panel (PDP) having a mesh-patterned partition, each square of which encloses one or more cells for constituting a display surface and a method for manufacturing the PDP.
A PDP is commercialized for a wall-hung TV set, whose screen size has reached 60 inches. PDP is a digital display device comprising binary light emission cells, so it is suitable for a display of digital data and is expected as a multimedia monitor. In order to increase applications of a PDP, a new panel structure is under development, which can provide a brighter and more stable display and can be manufactured in a high productivity.
2. Description of the Prior Art
An AC type PDP for a color display employs a surface discharge format. The surface discharge format has an arrangement of electrodes in which display electrodes that become anodes and cathodes in a display discharge for ensuring a luminance are arranged in parallel on a front or back substrate, and address electrodes are arranged so as to cross a pair of the display electrodes. In the surface discharge format PDP, a partition is necessary for separating a discharge for each column of a matrix display along the longitudinal direction of the display electrode (hereinafter referred to as the row direction). The partition also works as a spacer for defining a discharge space size in the direction of the panel thickness.
A partition pattern (a shape of the partition in the plan view) is broadly divided into a stripe pattern and a mesh pattern. The stripe pattern divides the discharge space for cells arranged in the row direction (i.e., in each column). In the stripe pattern, the discharge space of cell included in each column is not separated, so that exhausting of inner air and filling of discharge gas are relatively easy in a manufacturing process of a PDP. The mesh pattern divides the discharge space both in the row direction and in the column direction. A typical mesh pattern is a check pattern. A mesh pattern has an advantage in that the discharge is separated for each cell and that a fluorescent material is arranged on a side face of the partition so as to enclose the cell for increasing a light emission area. The mesh pattern, however, has a disadvantage in that a gap generated by subtle unevenness on the upper surface of the partition becomes an air path in the inner air exhaustion, so a resistance of the air exhaustion is large and it takes a long time for the process.
Conventionally, a partition structure of an overlaying form of the mesh-patterned partition and the stripe-patterned partition (this is called a composite pattern structure) is known. In this structure, since the discharge space is continuous as in the case of the stripe pattern, the air exhaustion resistance is smaller than in the case where the stripe-patterned partition is not overlaid. Furthermore, an improved composite pattern structure is disclosed in Japanese unexamined patent publication No. 4-274141, in which a stripe-patterned partition is provided with a hiatus for each cell, so that a grid-shaped air path (air exhaustion path) is formed for the gas to flow not only in the column direction but also in the row direction.
The above-explained partition having the composite pattern structure has a mesh-patterned partition whose banding portion in the column direction or the row direction is raised. There was a problem that the partition forming process becomes complicated for forming the above-mentioned structure on the inner surface of one of the substrate pair. Furthermore, if a mesh-patterned partition is disposed at one of the substrates and if a stripe-patterned partition is disposed on the other partition, the fluorescent material should be arranged on both of the substrates for increasing the area in which the fluorescent material is formed. In addition, a registration of the substrate pair in the assembling process is difficult. Thus, the partition having the composite pattern structure is adverse from the viewpoint of the productivity.
There is a method of forming the air path by cutting a part of the partition. However, this method may increase the number of manufacturing steps for the cutting process and may reduce the manufacturing yield since the partition can be broken by the cutting process.
An object of the present invention is to provide a PDP that has a good productivity of partition formation and air exhaustion process and can display more brightly and more stably than a PDP that has a stripe-patterned partition.
According to the present invention, a mesh-patterned partition is arranged on the inner surface of one of the substrates. The partition has low portions that form a mesh-like air path that travels through all of the gas-filled space enclosed by the partition in a plan view. For example, in a simple check pattern in which a line along the horizontal direction and a line along the vertical direction cross each other, the portion corresponding to the line along the horizontal direction is made low. In this case, the pattern width (the line width) of the portion corresponding to the line along the horizontal direction is made thicker than the pattern width of the portion corresponding to the line along the vertical direction so as to generate a height difference. The shrink quantity in the thick portion is smaller in the width direction but is larger in the height direction than the thin portion.